Range sensors are useful, for instance, in the construction and design of robots. Many ultrasonic range sensors have difficulty sensing proximate objects accurately within a meter of the sensor. As mobile robots programmed to perform specific automation sometimes need to operate with care toward proximate objects, it would be useful for a robot to be able to accurately sense proximate objects.
Ultrasonic range detectors that use only one range sensor cannot detect distances up to the front face of the sensor. These sensors have a proximity dead zone within which they are ineffective or inaccurate. A dead zone, in ultrasonic testing, is the interval following the initial pulse where the transducer ring down prevents detection or interpretation of reflected energy (echoes). In contact ultrasonic testing, the area just below the surface of a test object that can not be inspected because of the transducer is still ringing down and not yet ready to receive signals. Ultrasonic range detectors that use two range sensors cannot detect distances up to the front sensor face because the signal becomes blocked from sensor to sensor. These detectors also have a proximity dead zone within which they are ineffective or inaccurate. When objects are in a dead zone, the detector may or may not indicate something is in the dead zone. If it does indicate something is in the dead zone, these detectors will not be able to precisely identify the location of the object relative to the detector.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.